Lighting by sustained luminescence



May 17, 1938.. R. A. COUSTAL LIGHTING BY SUSTAINED LUMINESCENCE 2Sheets- Sheet 1 Filed Oct. 29, 1955 Patented May 17, 1938 UNITED STATESLIGHTING BY SUSTAINED LUMINESCENGE Rene Andre Coustal, Saint-Mam,France, assignor to Socit Anonyme Stella-Luis, Paris,

France Application October 29, 1935, Serial No. 47,326

. In France October 29, 1934 1' Claim.

The present invention relates to the technics of lighting by means ofmaterials the luminescence of which is electrically sustained, forinstance by means of high frequency high voltage currents.

In this art, use is made of lamps constituted by glass bulbs containingagas rarefied ,to cathodic vacuum and the inner face of which receives alayer of luminescent material. 10 By maintaining in the bulb a highfrequency high voltage current, the luminescence of the layer ofmaterial is sustained.

The present invention concerns improvements in the technics of thislighting. 13 These improvements relate both to the manufacture of thelamps and to their supply or energization and their applications.

They are mainly characterized by the following points, applicableseparately or in combination:

(a) The application of phosphorescent or fluorescent materials(particularly: zinc sulphide,

calcium tungstate, uranyl salts, and the like employed separately or. inmixtures) on the inner face of the bulb constituting the lamp, and intotality or in zones, is effected by moistening this face and byspraying on the moistened zone the luminescent material in powder form.

(1)) The liquid for moistening the inner face of the bulb is distilledwater.

:30 (c) The liquid for moistening the inner face of the bulb is asolution of zinc chloride (ZnClz) ((1) After drying the luminescentpowder, the bulb is connected to a source of vacuum and exhausted asperfectly as possible whilst the powder 3 is freed from gases, either bymoderate heating, or by intense energization at a high frequency, oragain by both these means applied simultaneously.

(e) After the bulb has been exhausted, a rare 40 gas, such as: helium,neon, argon, krypton or kenon, is introduced therein, whilst a highfrequency high voltage current is sustained in order to control,according to the brilliancy of the lamp, the pressure of the rare gasintroduced, this 5 pressure being usually much lower than one millimeterof mercury. The lamp is subsequently sealed and provided with aconducting socket constituting an electrodesupport.

(f) The lamps are constituted by spherical glass no bulbs with a singleelectrode or suspension cap.

, (grFor eliminating the localized brush discharges which in course oftime cause the neck portion receiving the lamp cap to break, the saidlamp cap is provided, at its lower part, with a 55 flange whichregularizes the distribution of the electric field, promotes cooling andcan eventually serve as lamp-shade.

(h) The metal cap of the lamp is secured to the neck portion of theglass bulb by direct aderence of a metal, such as tungsten, to theexclusion of any cement.

- generator giving a wave length of at least 6000 meters so as not todisturb wireless receptions.-

(I) For indoor lighting the wires supportingand feeding the lamps are inthe shape of aerials composed of multiple wires, arranged parallel to 20each other, or in fan-like fashion or otherwise, and supplied by a highfrequency high voltage current-generator, or a rotary current-generatoror a station provided with transmitting valves, or of the discharger orare type, the tuning being 0.- eiiected by means of self-induction coilsorof condensers.

(m) The lamps are fed by relaxation waves or oscillations andparticularly by utilizing dynatrons, singing arcs, so called Crystadynelay-outs 30 or of the singing crystal type.

(n) When the lamps are hung from a conducting wire supplied as an aerialwith high frequency high voltage current, the wire is surrounded byinsulating sleeves, preferably made of quartz, isolantite or materialshaving equivalent properties, which sleeves can constitute mechanicalstay members between two adjacent lamps.

The accompanying drawings illustrate, by way of example only, forms ofconstruction of the im- 40 provements according to the presentinvention.

Figs. 1, 2 and 3'i1lustrate forms of construc-' tion of lamps accordingto the invention.

Fig. 4 is a diagrammatic view of a road lighting installation. 4 5

Figs. 5 to 10 illustrate wiring diagrams of lamps according to theinvention.

The lamps according to the invention are constituted by a bulb made ofglass or equivalent material, having a general spherical shape with a ntubular neck portion which allows:

1--The moistening of the inner surface of the bulb, either by means ofdistilled water, or by means of an aqueous solution of ZnClz, and on thetotality or on certain zones only of this surface. 55,

of a fine powder, on to the moistened surfaces where they definitelyadhere after drying.

-'-The exhaustion of the bulb and the introduction of a rare gas thepressure of which is determintd by the brilliancy of the luminescentzones when the lamp is placed in a field of high frequency high voltagecurrent.

Concerning the introduction, which is moreover optional, of rare gasesinto the bulb, it is to be noted that these gases do not intervene forproducing a useful light, as is the case for lighting tubes (neon lampsfor instance). They simply promote the appearance and sustainment of thephenomena energizing the materials the lumi-.

nescence of which constitutes the only source of light.

As shown in Fig. 1, the bulb being sealed as usual for incandescentlamps, the neck portion 2 'is covered with a metal cap sealed by meansof a special cement and which constitutes an electrode and a means forsecuring the bulb on the supply wire. In the example of Fig. 1, the capwhich, moreover, must be devoid of projections capable of producinglosses of high frequency current, is provided with a hook 4 for hangingit from the supply wire 5. Other securing means, of the socket type forinstance, can obviously be provided. I

The material, the sustained luminescence of which produces the light, ispractically of indefinite duration and the wear of the lamps is causedby deterioration of the bulb itself. Thus, in the form of constructionshown in Fig. 1, the bulb may break at 2 after a certain time. The

breaking appears to be due to localized brush discharges which causelocal heating up of the For remedying thereto, use may be made of theform of construction shown in Fig. 2, in which the cap 3 is provided, atits lower part, with a flange 3 the periphery of which presents arounded ledge 3 in order to avoid losses of electric energy in theatmosphere. A rounded portion being also provided at 3 and distant fromthenarrow portion 2* of the neck, the localized brush discharges arethus eliminated, and, at the same time, it is possible to obtain:

A more regular distribution of the electric field producing andsustaining the luminescence,

A cooling of the cap which thus presents a large surface of contact withthe atmosphere.

The upper portion of the flange 3 being blackened and its lower facebeing polished, a lampshade is thus obtained.

In order to do away with cement ensuring the adherence of the cap 3 tothe glass of the neck portion 2 and which, as it never constitutes aninsulation, nor a perfect conductor, presents inconveniences, use may bemade of the arrangement'shown in Fig. 3, in which the metal of cap 3 isembedded in the glass of the neck portion 2 and of the bulb I. Use canalso be made of metals which, as tungsten for instance, adhere to glassand can constitute with the latter a real weld. The inner surface of cap3 is coated with welded to the latter.

For allowing the neck portion 2 to resist to the effects of temperature,it can be-made of quartz and it can be welded,by known processes, to theglass which constitutes the bulb proper.

If for constructional requirements the cap is to be sealed by means ofcement, use can be made of the cement indicated hereinafter whichbehaves as a dielectric having but small losses in high frequencycurrent.

This cement is constituted by an alloy of sulphur and paraflin and iscomposed for instance of '75 parts of sulphur and 25 parts of paraflinhaving a high melting point.

Lamps according to the invention can be used for lighting roads. Inthe'installation diagrammatically illustrated in Fig. 4, wires 6 aresupported, through the medium of insulating chains 7, by posts 8arranged at intervals along a road and connected, at one end, to thesecondary winding 9 of 2. Tesla transformer, the primary winding ill ofwhichis fed by a high frequency and high voltage alternator ll giving,for instance, a wave length of 10 kilometers, the secondary windingbeing perfectly tuned. The lamps i2 are secured to wires 6 at anydesired distance apart and give, for a reduced consumption of energy, adiffused light very pleasant to the eye.

The electric fields sustaining the luminescence are obtained by dampedwaves or by sustained waves.

Damped waves have the advantage, concerning the energization of lamps ofthe above type, of giving rise to high voltage peaks allowingutilization of a relatively reduced mean potential. On the contrary, thefluctuations due to the very nature of the current which is notsinusoidal, give rise to irregularities in the luminescence.

With sustained waves, a regular energization is obtained, but, on theother hand, the absence of voltage peaks necessitates the use of a.higher supply mean potential.

For the purpose of deriving profit from the advantages of each of themodes of supply indi cated,above, without suffering from theinconveniences of the same, the invention concerns the new application,for feeding lamps of the type indicated, of relaxation waves oroscillations. These waves have voltage peaks and a regularity comparableto that of sustained waves, and, in any case, sufiicient for preventingthe production of fluctuations perceptible to the eye.

-The invention includes in its scope any generating means suitable forthe production of these relaxation waves and particularly the following:

Dynatrons I Singing arcs So-called Crystadyne lay-outs, that is to saysinging crystals, such as zincite.

Relating to these latter means, the invention concerns the newapplication of marcasite the properties of'which, as far as theapplicant is aware, have not been used in Crystadyne lay-outs.

Fig. 5 shows a generator for the production of relaxation oscillations,This generator is constituted by a valve having two inner electrodes l4and [5 connected to the circuit iii of a source of supply of highfrequency high voltage current, on which electrodes is shunted acondenser l'l.

Fig. 6 shows a feeder lay-out for feeding lamps IS. The latter are ofthe suspension hook type described above. They are hung from the wiresof the feeders i8 and in electric contact with the same through the hookconnected to their electrode. I

In the lay-out of Fig. '7, the lamps l9 are interposed between thefeeders I 8, by two hooks 20, or securing means provided with'suitablecontacts and connected to the electrodes of the lamps.

In Fig. 8, an aerial wire or feeder [a is s1n'- 5 rounded by sleeves 2|made of quartz, isolantite or like material, which serve as mechanicalstay members between two adjacent lamps I! hung from the wire as thelamps I! of Fig. 6. The losses of energy for the wires are thus reducedas explained above.

In Fig. 9, the lamps l9 are externally attached to the insulatingsleeves 2| of Fig. 8, either by their suspension hook, or, preferably,by a conducting socket 22, in order to provide condensers allowing theaerial or wire Hi to be better defined.

In Fig. 10 the lay-out illustrated avoids an excessive coefficient ofdamping of the aerial circuit. At a certain distance from thesupply\wire,

. or from the feeder I8, is arranged a wire parallel thereto and fromwhich the lamps l9 are hung. The wire 23 is insulatedat its ends or isconnected as an aerial turned on the wave of the aerial constituted bythe supply wire. This tuning can be obtained either by the own wavelength of the wire II, or by connecting the latter to a closed circuitcomprising a capacity and a tuning self-induction coil, or again byearthing it, through a self-induction coil and a. capacity. What I claimas my invention and desire to secure by Letters Patent is: r

In an installation for supplying lamps with electric energy, comprisinga transparent bulb for visible radiation and coated with a layer of asolid luminescent or phosphorescent' material.

the said lamps comprising one or two electrodes, a free conducting wire,a source of electric energy connected to the said wire for producingoutside the same a variable electric field, sleeves of insulatingmaterial surrounding the said wire, conducting sockets surrounding thesaid sleeves and connected to one of the electrodes, lamps renderedluminescent by the action upon the layer of luminescent orphosphorescent material of the electric field produced outside the saidwire.

Rant ANDRE cons-ran

